植物转基因表达调控研究组

植物叠加中的转基因沉默

在植物基因工程中,外源目的基因的表达水平因不同的转化事件而不同。即使使用强启动子,转基因也会在某些转基因株系中不表达,称为转基因沉默现象。引起基因沉默的因素很多,包括外源基因在基因组中插入的位置,外源基因在基因组中的拷贝数,外源基因在基因组中的整合方式等。利用基于重组酶的基因定点叠加,可以实现外源基因精确完整地整合到基因组的特定位置,从而避免因为插入位点、整合方式不完整、拷贝数多等因素引起的转基因基因沉默。我们的研究结果还发现,基因叠加过程中,随机插入事件与定点整合事件同时发生,那么也会引起基因沉默。我们正在利用基因沉默的株系,研究引起基因沉默的分子机制。

Transgene silencng in gene stacking

In the process of plant gene engineering, different transformation events result in different levels of exogenous gene expression. Although driven by a strong promoter, the transgene remain unexpressed for certain transformation events, to which is referred as transgene silencing. Multiple factors may trigger transgene silencing such as integration position, copy number, and integration pattern of transgene into the host genome. Accurate and single copy of transgene integration into specific position of genome can be achieved by recombinase mediated gene stacking, which lowers the chance of gene silencing caused by insertion into heterochromatic region, incomplete integration, and multi-copy insertion. Transgene silencing was observed when random insertion happened together with site-specific integration in some recombinase mediated gene stacking events. Currently, we are focusing on these silenced lines to dissect the molecular mechanisms of transgene silencing.

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